   #include<stdio.h>
   #include<sys/types.h>
   #include<unistd.h>
   int main()
   {
     int a=1;
     int ret=fork();
     printf("hello world\n");

    if(ret>0)
    {
      printf("you can see me!!!\n");
      printf("%d\n",a);
    }        
    else                                                                              
    {                                                  
      printf("oops! you can see me!!!\n");
   printf("%d\n",a);                                                                                                                     
    }          
    sleep(1);
  while(1)                      
   {                                                  
   printf("hello wkd!:pid: %d,ppid: %d\n",getpid(),getppid());
   sleep(1);       
  }                                            
    return 100;                          
  } 

